Adjustable propeller



Dep. 20, 1938. H. RElssNER,

` ADJUSTABLEPROPELLER Filed Sept. 9, 1936 2 Sheets-Sheet l Fig. a.

Dec. 20, 1.938.

H. REISSNER ADJUSTABLE- PROPELLER Filed Sept. 9, 1936 2 Sheets-Sheet?Patented Dec. 20, 1938 UNITED STATI-:s

PATENTl CFFICE Application September 9, 193s, sei-iai No. 99,933

In Germany September 12, 1935 8 Claims.

My invention relates to adjustable propellers in which the reactiondevice for deriving the adjustment forces from the rotation of thepropeller shaft is formed by an air blade brake or similar device whichis disposed on the propeller` side opposite the propeller bearing.

One object of my invention is to produce an adiustable propeller inwhich the air brake shaft drives two gears rotating in oppositedirections, which gears can be coupled alternatively, to the blades ofthe propeller so as to increase or decrease the pitch of said blades.According to my invention the gears are constructed as bevel gearsrotatable on an adjustment shaft disposed transversely of the propellershaft. Another object of my invention is to provide couplings betweenthe gears and the propeller blades which cannot become jammed under theinfluence of the centrifugal forces set up by the rotation of thepropeller. For this purpose my device is constructed with frictioncouplings axially displaceable on the transverse adjustment shaft. In afurther development of my invention, the couplings are either directlyconnected with the centrifugal. masses or they are formed themselves ascentrifugal masses.

A further object of my invention will be seen from the followingspecication and claims.

My invention is illustratively exemplified in the accompanying drawingsin which:

Figs. 1 and 2 are a longitudinal section and a part front view,respectively of the gearing of an oil controlled embodiment of myinvention.

Fig. la shows a modification of the coupling mechanism, illustrated inFig. 1, likewise in longitudinal section. Y

Figs. 3 and 4 are a longitudinal section and a part front view of amechanical embodiment controlled by a centrifugal regulator or governer.

Fig. 5 is a longitudinal section oi an embodi ment with a centrifugalgovernor and frictioncouplings. Y

Fig. 6 is a partial longitudinal section of a construction with wormengagements instead oi couplings. I v

According to Figs. 1 and 2 blade bases i are disposed rotatably inbearings i of a boss-part 2. Worms 5 engage in worm wheels d ofthe-blade bases, and further Worm-wheels 6 on the shafts of worms 5 areengaged by worms l on a cross shaft 8 carrying medially thereof aworm-wheel 9. The worm wheel 9 is engaged by a worm i0 of a transverseadjusting shaft ii. ing-shaft ii carries rotatably thereon bevelwheelsi2, i3 permanently engaged by a bevel- The adiust- (Cl. 17o-163) wheelI4 on a brake blade shaft i5, which latteris disposed freely rotatablein a nave-projection It and carries a nave hood l1 with brake-blades i8.The brake-blades I8 are constructed as screw-blades with a. pitchopposite to that of the propellerfblades, whereby a rotation of theadiusting implement may be derived from the passage-windiof the iiyingaeroplane when the propeller is at rest. l

The bevel-wheels i2, i3 may be coupled alter- 10 natively to theadjusting shaft il. For this purpose the bevel-wheels are provided withbevel coupling-surfaces I9, 20 and with movable cones 2|, 22,constructed as pistons within cylinders 23, 2l of the .bevel wheels. The'cones 2i, 22 are axially slidable but not rotatable relative to theadjusting shaft. Conduite 25 for oil under pressure are s connected byrotary stumng-glands to the hollow-bored ends of 'the adjusting shaftIl, that they conduct the oii under pressure into 20 the space behindthe coupling-pistons 2i, 22 and the couplings can thereby be thrown intoengagement. The pressure-oil conduits 25 are connected to thecontrolling conduits leading to the pilots e or cockpit by oil channelsin the propeller 25 pfac bearings or by special introducing rings in anyusual manner, so that the pilot can increase or decreasethepropeller-pitch optionally by employing the motor oil pressure vpump ora different Oil-supply. 3Q

Instead of the cylinders it, 2i for oil under pressure electric coils 2ican be provided, as shown in Figic, andthe conduits 2t for the oil underpressure are then replaced by electric leads 25' with lslip-ringconnection 252 to the 35 pilots place. In this arrangement the couplingcan be effected by electro-magnetic displacement, the coupling cones di,lli being constructed of suitable material.

In all cases the manipulation of the regulating o conduits it can beautomatically eected instead of by hand by a centrifugal regulator orgovernor amxed to the motor or bya special regulator, and

. theregulator can eventually be disposed on the propeller so that onlya single conducting means for oil under pressure or for electricity needbe led into the propeller.

.According lto Figs. 3 and 4 the blade-bearings i, 2, 3 and. theirworm-wheels i are substantially the same as in the previousconstruction. However, worms 5a both engage the worm-wheels il on thefree propeller side, and worm-wheels ta on the shaft of worms 5a engageworms la on a short intermediate shaft 9a. An additional wormwheel 3adisposed centrally of the shaft a engages a worm Ilia on the adjustingshaft Ila, which, in the embodiment of Figure 3, extends transversely ofthe blade-axis of the propeller. For the drive of the adjusting shaftthere are provided bevel wheels I2a, I3a in engagement with a wheel I4disposed on the brake-blade shaft I5. The bevel wheels I2a, I3a aredisposed independently of the adjustment shaft I I in bearings 26 on thenave 2, so that they leave said shaft unaffected as long as the coupling2Ia, 22a,

constructed as a jaw-coupling, is not thrown into gear. The throwinginto gear in one direction or another is effected automatically by acentrifugal regulator, the spindle of which is formed by the adjustingshaft IIa itself, which carries a 'centrifugal weight 21. 'I'he weight21 is so compensated relative to the nave part 2 by a governor spring28, that it keeps the two couplings 2 Ia, 22a out of engagement at thedesired standard speed of revolution while 'it engages the coupling forincrease or decrease of pitch upon overor under-stepping of saidstandard speed.

In order to automatically terminate the adjustment of the blades whenthe smallest permissible pitch positions have been reached the bladebase 3 is provided with a projection 29 opposite a ram 30 displaceablydisposed in the nave 2. The ram 30 actuates a two armed lever 3l, whichpresses axially on the adjusting rod I I a in the di- ,frection of thecentrifugal force of the regulator weight 21. This disengaging devicethus uncouples the coupling 2Ia, as soon as the smallest permissiblepitch has been reached.

According to Fig. the blade root parts and their bearings areessentially the same as in the previous figures. The couplings arebevel-couplings 2lb, 22h, which are disposed axially movable and securedagainst rotation on the adjusting rod IIb which is fixed against axialdisplacement not axially movable. 'The adjusting rod IIb is formed as ahollow shaft traversed by axially displaceable regulating rams 32, 33carrying centrifugal weights 34, 35 and regulator springs 39, 31 on theend portions thereof projecting from said hollow shaft The spring 31abuts against the brake 31 rigidly supported on the propeller hub. Asboth rams 32, 33 are drawn outwardly by thecentrifugal force, thecoupling 2lb of the one ram is coupled outwardly and the coupling 22b ofthe other ram is uncoupled outwardly, whereby both couplings are put outof engagement at a chosen standard, and upon over or under stepping ofsaid speed the one or the other gear is thrown into engagement forincreasing or decreasing the pitch.

The centrifugal weight 34 operating on increasing the pitch is ofmagnetizable material, and surrounded by a solenoid coil 38, which canbe fed from the pilots seat with an electric current through aregulating resistance. If this coil is fed with increasing current, itdraws the centrifugal weight 34 increasingly outward, so thatthecoupling 2lb operating on increase of pitch,

can be brought into action by centrifugal displacement of the weight 34on a speed of the propeller insuf'cient to cause increase of the pitchand 'the propeller is adjusted to a smaller standard speed. For thecentrifugal weight 35 operating on the decrease of slope an electriccontrol is unnecessary, because the adjustment of the blades to thesmallest permissible pitch always remains harmless. As an uncouplingdevice for the smallest pitch a toothed rack ram 39 -is provided whichis axially moved by an intermediate worm 40, so as to bring a projection4I on the ram 39 into engagement with a flange 42 of the coupling nu onthe attainment of the smallest pitch, thereby disengaging the coupling.

In the embodiment illustrated in Figure 5, the whole main 'part of theadjusting device is disposed in a special housing 43, which is removablewith the whole'gear from the nave 2. This arrangement allows forattaching different kinds of regulating devices to one and the samepropeller, corresponding to different requirements for special objects.f'

According to Fig. 6 worms 5a and worm wheels ra lead from the bladeworm-wheels 4 to two ransverse worms 44, which are connected withworm-wheels 45. The worm-wheels 45 are constructed similarly to spurwheels, so that they can come into engagement as well with right-handedas with left-handed worms. Between these wheels a right-handed worm 46and a left-handed worm 41 are disposed on a shaft 48, which is disposedaxially movable but not rotatable in the hollow blade brake shaft I5a.Two magnetic coils 49, 50 are provided in the nave projection I6 andthere between the axially movable shaft 48 carries an armature 5I sothat by current supplied at choice tothe coil 49 or 50 the worm 41 or 46can be thrown into engagement and the adjusting device can be rotated inone or the other direction.

The two adjusting wheels 45 may be connected with each other byimmediately interengaging gears 52, 53 for exact synchronization so thatalways each of the worms 46, 41 engages in uniform manner with them.

The switching in of the magnetic coils 49, 50 can be effected in allkinds of ways already mentioned, e. g. by hand through slip-rings or by.a regulator through slip-rings or by a regulator mounted directly withinthe propeller.

I claim:

1. An adjustable propeller, comprising a. propeller shaft, a hub,propeller blades rotatably arranged on said hub, a brake shaft parallelto the propeller shaft and rotatably supported by said hub, an air bladebrake on said brake shaft, an adjusting shaft rotatably carried on saidhub transversely of said propeller shaft, two 'gears rotatable on saidadjusting shaft, means on said brake shaft todrive said gears inopposite directions, coupling means comprising two coupling elementsaxially displaceable on said transverse shaft and adapted to engage saidgears respectively to transmit the movement of either of said gears atchoice to said transverse shaft and a gearing,r mechanism to transmitthe rotation of said transverse shaft to said propeller blades, wherebythe pitch of the latter can be increased and decreased, respectively.

2. An adjustable propeller, as claimed in claim 1, in which said axiallydisplaceable coupling elements on said transverse shaft comprise asutilcient mass to be displaced by centrifugal force at a predeterminedspeed of propeller revolution.

3. Adjustable propeller as claimed in claim 1, wherein said two gearsare formed as bevel gears and said driving means on the brake shaftconsists .of a third bevel gear in engagement with said first-mentionedbevel gears.

4. Adjustable' propeller as claimed in claim 1, wherein said couplingmeans comprises further electromagnetic means adapted to bring one ofsaid coupling elements in engagement with the corresponding gear.

5. Adjustable propeller as claimed in claim 1, wherein said couplingmeans comprises further a centrifugal governor controlling said couplingelecentrifugal direction, at low revolution speeds of the propeller.

7. Adjustable propeller as claimed in claim 1, comprising further. amovable control element operatively connected with the gearing mechanismtransmitting the rotation of said transverse shaft to the propellerblades, said movable control element being constructed and arranged todisengage said coupling means from the corresponding gear on attainmentof the lowest permissible pitch.

8. Adjustable propeller as claimed in claim 1, wherein the gearingmechanism transmitting the rotation of said transverse shaft to thepropeller blades includes transverse worms and worm gears on the bladeroots engaged by said transverse worms, and the entire adjustingdeviceincluding said transverse worms is removably secured to thepropeller.

HANS REISSNER.

